A series of seven thiophene-based oligomers were prepared as hole transport materials. The DBATn series is composed of six oligothiophenes (n = 1–6) capped with two dibutylaminostyryl electron donating moieties. The band gaps for these compounds range from 2.47 to 2.19 eV. It was found that the bis(amino) substituents control the ionization potential, while the electron affinity and energy gap depend directly on the oligothiophene chain length. The bulk crystalline properties of these materials depend strongly on whether the number of thiophene rings in the bridge is even or odd. This results in the compounds that have an odd number of thiophene units in the bridge to exhibit depressed melting points with respect to the structures with an even number of rings. X-Ray structure determination was obtained from single crystals of DBAT1 and -2. Good solubility, thermal stability and film forming properties were found throughout the series of compounds. A seventh compound, DH2E4T, was also prepared. This molecule is comparable to α,ω-dihexylsexithiophene but with greater solubility and reduced optical band gap (2.32 eV).
制备了一系列七个基于
噻吩的低聚物作为空穴传输材料。
DBATn系列由六个低聚
噻吩组成(n=1-6),两端连接两个二丁
氨基
苯乙烯电子供体单元。这些化合物的能隙范围从2.47到2.19电子伏特。研究发现,双
氨基取代基调控电离电位,而电子亲和势和能隙直接取决于低聚
噻吩链的长度。这些材料的块体晶体性质强烈依赖于桥接
噻吩环的数目是奇数还是偶数。结果导致桥接中有奇数个
噻吩单元的化合物相对于有偶数个环的结构表现出较低的熔点。从
DBAT1和-2的单晶获得了X射线结构测定。在整个化合物系列中,均表现出良好的溶解性、热稳定性和成膜性。还制备了第七个化合物DH2E4T。这种分子与α,ω-二己基六
噻吩相当,但溶解性更好,光学能隙更小(2.32电子伏特)。